It's Part of my Chemistry
by SassyGayNine
Summary: Blaine doesn't like it when other guys flirt with Kurt, so he decides to remind Kurt exactly who he's dating. Smutsmutsmut. Future!Klaine. PWP.


**Review, please.**

**I own nothing and no one.**

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><p>"No, really! You should come out some night, it's ridiculous," A man with sandy blonde hair laughed, waving his hand excitedly, while walking down the hall. The man he was talking to laughed and shook his head, rolling his brilliant blue eyes. The pair stopped outside a door and looked at one another. "Whatever, Kurt, you're missing out," The first man said, running a hand through his hair and flashing the other man, Kurt, a winning smile. Kurt rolled his eyes again and let out a musical laugh before place his hand on the other man's well toned bicep, "I'm sure I am, Derek. I have to go, though. I'll see you tomorrow?" Derek nodded and watched as Kurt turned to walk back down the hall, his maybe straying down towards Kurt's swaying hips and ass as he walked.<p>

Kurt heard Derek's door open and close just as he got to his own apartment door. He pulled out his keys to unlock the door but it was ripped open before he could even try. "Hey, baby," Kurt said, smiling at his boyfriend, completely oblivious to the hard look on his face. Kurt stepped into the apartment, his boyfriend shutting the door, and dropped his bag to the floor before taking off his jacket and toeing off his shoes. Kurt turned around to see Blaine, his boyfriend, hadn't moved from his spot by the door. Kurt furrowed his eyebrows and took a step toward him. He reached a hand out and gently cupped Blaine's face, "What's wrong?"

Blaine's normally honey hazel eyes were slightly darkening as he stared back at Kurt. "Who was that? Out in the hall?" His voice was lowering too, getting rougher, even. Kurt blinked slowly, "Derek? He's in one of my classes. We just figured out we live in the same building. Why?"Blaine didn't answer right away and Kurt honestly couldn't figure out what was wrong with Blaine today. Kurt leaned in to kiss Blaine quickly before starting to walk further into the apartment. "Is he gay?" Blaine asked, walking after him. Kurt looked over his shoulder at Blaine, thoroughly confused, "Yeah, he is." Kurt walked into their bedroom and started to unbutton his shirt while Blaine just stopped and leaned against the doorway, crossing his arms over his chest.

"He invited me to go to some club with him sometime," Kurt said off-handedly while he shrugged off his shirt and tossed it into the hamper. Blaine gritted his teeth, "What'd you say?" Kurt looked over at Blaine and raised his eyebrows before walking over and taking his face in his hands. "I said no, because we're an old married couple, remember?" Kurt joked, kissing Blaine quickly on the lips before turning around to take off his undershirt as well. Blaine's tongue ran over his lips before he sighed, "Did you tell him you have a boyfriend?" Kurt tossed his shirt into the hamper and sat down on the bed to take off his socks. "No, it didn't come up. Blaine, what's going on?"

Blaine just shook his head and shrugged, "You realize guys wouldn't ask you to go out if you tell them you have a boyfriend, right?" Kurt stood up and put his hands on his hips, fixing Blaine with a glare, "Is that what this is about? You're jealous?" Blaine pressed his lips together to form a hard line and just stared back at Kurt, not wanting to say anything else. Kurt, however, only smirked at his boyfriend. "That's it, isn't it? You don't like the fact that another guy can find me attractive? Then, I guess, I shouldn't tell you about the guy in my morning class who stares at my ass when I leave class? Or, the guy who flirts with me at the coffee shop?"

Kurt raised an eyebrow at Blaine. Blaine's eyes narrowed at his face hardened. Kurt laughed and turned around to pick up his socks and toss them in the hamper. When he stood up he could feel Blaine's front pressed flush against his back and his hot breath hitting the back of his neck. Blaine's hands gripped Kurt's hips tightly to hold him in place. "Blaine…" Kurt started, unsure of what his boyfriend was doing. Blaine shook his head and nipped at Kurt's shoulder. "You're mine," He breathed, the grip on Kurt's hips was tightening, making him whimper softly. Blaine's mouth attached to Kurt's neck, sucking and biting at the pale flesh while his hands quickly undid Kurt's belt and pulled it out of its loops before dropping it to the floor.

"Fuck!" Kurt yelled out when Blaine sunk is teeth into the spot where he had been kissing. Blaine slid the button of Kurt's jeans out of place and let his hands run down the front of Kurt's thighs. "Mine," Blaine breathed as he pulled down the zip of Kurt's jeans and started to slide the jeans down his legs. Kurt's head tipped back and rested on Blaine's shoulder. Blaine looked over at him and crushed their lips together. "Mine," He spoke quickly before reattaching their mouths. The kiss became frantic, all tongue and clashing teeth while Kurt kicked off his jeans and Blaine's hand grabbed Kurt's cock through his boxer-briefs.

Blaine bit down onto Kurt's bottom lip and pulled slightly, making him moan loudly. "I'm the only one who gets to see you like this," Blaine said, releasing Kurt's lip. Kurt could only nod as he breathed heavily, his eyes glossing over. The hand gripping Kurt through his underwear moved and dipped under the waistband to wrap around his cock. Kurt whimpered softly and his hips jerked up into Blaine's hand, making the slightly shorter man chuckle. He licked at Kurt's lips before crushing another kiss to them as his hand began to move slowly. Blaine pulled his lips away and Kurt let out a particularly high pitched whine. "God, the sounds you make, Kurt. The sounds you make for me," Blaine grunted as he gave Kurt's cock one more pump before pulling his hand away.

Kurt opened his mouth to say something but Blaine gave his backside a slap and pushed him forward so they were in front of the dresser. Blaine ran his hands up and down Kurt's bare sides until the settled on his hips again. "Bend over," Blaine's voice was gravelly and made Kurt moan at the sound of his before complying. He bent at the waist, his chest lying flat on the top of the dresser and his hands gripping the edge tightly. Blaine kissed the top of Kurt's spine while his hands hooked into the elastic top of his underwear and yanked them down. Blaine grabbed Kurt's ass and squeezed roughly, reveling in the mewls of pleasure Kurt was making in response.

Blaine took a step back from Kurt and quickly pulled off his shirt and pants before walking over to the bedside table. Kurt turned his head to watch Blaine bend over and search the drawer, his eyes lingers on the bulge in the front of his boxers. Kurt licked his lips as he watched Blaine close the drawer and stand up straight and he whimpered a little when he saw the small bottle in his boyfriend's hand. Blaine smiled as he walked back over to Kurt. He placed the bottle on the dresser top next to Kurt before kneeling down to the floor. Blaine ran his hands over the curve of Kurt's ass slowly before he gently pulled the cheeks apart and was eyelevel with his hole.

He stayed like that for a while, just staring as Kurt's hole flexed and relaxed under his gaze. "Blaine," He whimpered softly from above. Blaine cocked his head to the side to see Kurt had turned his head to look down at him. "Yes, Kurt," Blaine asked, his hands gently squeezing the globes they held. Kurt swallowed hard and stared back at Blaine's dark, lust blown eyes, "Please, _please_, do something." Blaine smirked and winked at Kurt before turning back. He leaned forward and quickly swiping his tongue over the hole. Kurt whines and lays his forehead against the dresser as Blaine does it again. He hardened his tongue to a point and pushed against Kurt, not enough to enter but enough pressure to make him squirm. "Blaine, please."

Blaine pushed a bit harder until his tongue goes past the ring of muscles and Kurt sighs loudly. Blaine probed more, his tongue sinking further into Kurt before he pulled it out, making Kurt whine again. "Do you want me to fuck you, Kurt?" Blaine asked before licking at his hole again. Kurt moan and his hips pushed back, trying to get more contact out of Blaine's tongue. Blaine stood up and grabbed the bottle of lube off of the dresser and quickly squirted some into his hand. He slicked up his fingers and pressed two against Kurt's opening. Kurt whimpered as Blaine pushed them in quickly. "Do you like that, Kurt? Or, are you whining because you just want my cock?"

The fingers inside of Kurt quickly began to pump in and out. With each insertion they were at a different angle, hitting a new spot inside of Kurt, making him moan into the dresser and grip the edges tighter. "Oh, fuck!" Kurt cried out, his back arching dramatically, as Blaine's fingers brushed up against his prostate. Blaine chuckled softly and did it again, watching as Kurt's body shook and twitched. "Please, Blaine, please," Kurt begged, looking over his shoulder at his boyfriend. Blaine looked at Kurt's dark, hooded eyes, the light sweat that was making his hair mat to his forehead and licked his lips slowly. "What do you want, Kurt? Tell me."

Kurt groaned and let his head fall against the dresser as Blaine's movement sped up, hitting his prostate every time. "I need you to fuck me, Blaine. Please," Kurt's muffled voice cracked slightly at the end of his plea, making Blaine smirk. "You _need_ it, Kurt?" He asked as he slowly slipped in a third finger, stretching Kurt carefully but not halting in his pumping. Kurt could only nodded and make a grunt in confirmation. "How bad do you need it?" Blaine asked, rubbing his fingers against Kurt's prostate. Kurt softly banged his head against the dresser and let out a high pitched gasp every time Blaine's fingers brushed up against his prostate.

"I need you to fuck me, Blaine. Please. Fuck me. I might actually die if you don't. _Please._" Kurt rambled as he begged and pushed back against Blaine's fingers. Blaine pulled his finger out of Kurt quickly, making him whine at the loss. Blaine brought his palm down against Kurt's full ass quickly. The sound of flesh on flesh echoed in their small apartment. Kurt whimpered and screwed his eyes shut; the need to come was becoming so great he felt tears in his eyes. Blaine took the bottle of lube and slicked up his cock as he positioned himself behind Kurt. "You are such a little cockslut. Aren't you, Kurt? Just begging for me to fuck you, to fill you full of my cock."

Kurt moaned and nodded as he felt the tip of Blaine's cock pressing against his entrance. Blaine wasted no time in pressing into Kurt to the hilt, making them both moan and sigh. Blaine pulled almost all the way out before slamming back into Kurt, pushing the other man's hips into the side of the dresser. Blaine spoke again, punctuating each word with a sharp thrust into Kurt, "Such. A. little. cock. Slut." Kurt moaned loudly and nodded again. Blaine's hands came down and gripped onto Kurt's hips so tight that finger shaped bruises were sure to be there by morning. "My cockslut," Blaine growled as he relentlessly pounded into Kurt, making the dresser shake and hit against the wall. Blaine shifted slightly so that his cock hit against Kurt's prostate hard. "_Oh fuck_. Yes, Blaine, yes. I'm yours. Your cockslut. Yours, no one else's. _Fuck. _Harder, please," Kurt's voice was shaking as he begged.

A warm, bubbling sensation was building up inside him as Blaine continued to thrust against his prostate sharply. Blaine could feel his orgasm swiftly approaching, too. "You're going to come without me having to touch your cock, aren't you?" Blaine asked, his thrust becoming erratic. Kurt grunted loudly and nodded, unable to find his voice. Blaine hit the bundle of nerves inside of Kurt once, twice and Kurt was suddenly screaming his release and shaking as he came hard over his stomach and dresser top. His body clenched harshly around Blaine, making him groan. "Fuck, Kurt," Blaine moaned as his orgasm hit him too. He was shooting thick ropes of come inside of Kurt as his thrusting slowed down and eventually stopped.

They were both breathing heavily, completely spent. Blaine slowly pulled out of Kurt, both of them wincing as he did so, and wrapped his arms around Kurt's waist to pull him up and off of the dresser. Blaine all but carried Kurt to the bed and laid down next him, face to face. "I love you," Kurt said softly, still breathing heavily. Blaine nodded and kissed him tenderly, "I love you too."


End file.
